1. Field of the Invention
The invention relates generally to communication over networks, and more particularly to signal mapping prior to transmitting the signal over a network.
2. Background of the Invention
Electronic information is often shared through computer networks. These networks can vary in size from small networks of just a few devices sharing information to large-scale global networks, such as the Internet. Regardless of the size, there must be a mechanism in every network to transport information. Information in the form of electrical signals are often transported through copper cable; information in the form of optical signals are transported through fiber optic cables; and other electromagnetic waves can be transported through the air.
FIG. 1 shows several devices connected together through an optical network 110. Optical networks have several advantages, including a large bandwidth, low susceptibility to interference, light-weight cables, and an ability to transmit information digitally rather than in analog form. Devices attached to an optical network might include a switch 120, a server 140, and a network attached storage (NAS) 150.
Switch 120 is a device that filters and forwards packets of information between local area network (LAN) clients 130. Clients 130 can include a desktop computer, laptop, personal digital assistant (PDA), printer or other network attached device.
Server 140 controls network resources. For example a file server stores files, a print server manages one or more printers, a network server manages network traffic, and a database server processes database queries. Servers 140 can include UNIX servers, NT servers, Windows 2000 servers, LINUX servers, or other computer systems attached to the network. Network attached storage 150 is a special type of server 140 that is dedicated to file sharing and cannot perform other functions, such as authentication or file management.
Each device 120, 140, and 150 must have an interface circuit 160 installed in order to communicate across optical network 110. Signals on optical network 110 travel at a rate faster than devices 120, 140, and 150 can process. Also, optical signals are serialized (travel bit by bit) and devices 120, 140, and 150 use parallel data streams. Therefore, interface circuit 160 translates serial optical signals into a slower, parallel data stream when receiving optical information, and conversely translates parallel data streams into faster, serial bit streams when transmitting information.
Many interface circuits 160 known in the art use older Ethernet protocol standards. Specifically, these older Ethernet protocols allowed throughputs of only 10 megabits per second over a network medium. However, a newer, faster, 10-Gigabit Ethernet standard has recently been defined. Old interface circuits 160 cannot be readily adapted for use with the new standard because both translations from the transport medium to the devices on the network and collision detection mechanisms function differently.